Comparative Histochemical and Biochemical Analysis of Endogenous Receptors for Glycoproteins in Human and Pig Peripheral Nerve

Endogenous sugar-binding proteins were localized in sections of human and pig peripheral nerves by the application of two types of labelled ligands: neoglycoproteins (chemically glycosylated carrier proteins that had proven to be histochemically inert) and desialylated, naturally occurring glycoproteins. These proteins allowed evaluation of the presence and distribution of endogenous receptors for carbohydrates, commonly present in cellular glycoconjugates. (Neo)glycoprotein binding was similar, but not identical, for the two types of mammalian peripheral nerves. The pig nerve differed from the human nerve in more pronounced staining when using different types of beta-galactoside-terminated (neo)glycoproteins and charge-carrying neoglycoproteins, such as bovine serum albumin, bearing galactose-6-phosphate residues, glucuronic acid residues, and sialic acid residues. Comparative biochemical analysis of certain classes of sugar receptors by affinity chromatography and gel electrophoresis revealed the presence of sugar receptors that can contribute to the histochemical staining in a pattern with certain significant differences among rather similar expression for the two species. The assessment of sugar receptor distribution by application of (neo)glycoprotein binding among morphologically defined regions in nerves may hold promise in detecting developmental regulation and changes during nerve degeneration and subsequent regeneration after trauma or pathological states. Correlation of these results to changes in the structure and abundance of glycoconjugates, which are the potential physiological ligands of endogenous sugar receptors commonly detected by plant lectins, may help to infer functional relationships.